Design,Synthesis And Performance Research Of Novel Near-infrared Luminescent Material Based On Rhodium(Ⅲ) Complex

Near-infrared luminescent material is a kind of optoelectronic functional material with emission wavelength from 700 nm to 2500 nm.At present,near-infrared luminescent material has an increasingly important position in military,medical and energy.This is precisely the characteristics and good performance of near-infrared emitting materials that make it so widely used.Organic near-infrared electroluminescent materials are mainly formed by fluorescent materials and phosphorescent materials.The difference between organic near-infrared phosphorescent materials and fluorescent materials is that their theoretical internal quantum efficiency can reach 100%.Due to its excellent characteristics,it has become a research hotspot of near-infrared luminescent materials.According to the reports published so far,the electron transfer method of transition metal complexes that can theoretically reach 100%due to their own internal quantum efficiency and strong metal-ligand charge transfer is favored by researchers.In this experiment,Rhodium in Platinum Group Metals was used to study.Platinum Group Metals have provided great strength for the development of transition metal complexes,rhodium,the last transition metal in the platinum family,has an unknown challenge and great prospect in the near-infrared organic light-emitting materials.Even though Rhodium has a similar structure to its iridium cousin,it still does not glow as well as the iridium complex.However,by selecting a strong donor ring metal ligand with a lower ligand（IL）state,the d-d excited state can be enhanced and a lower emission excited state can be introduced to enhance the luminescent properties of Rhodium complexes.But at present,the luminescence of Rhodium complex can only reach the orange region,and the increase of conjugated structure can enhance the absorption and emission wavelength of Rhodium complex,which shows red shift in the luminescence spectrum.On this basis,two series of ring-metallized Rhodium complexes,dpbq and dtbq,have been designed and developed.These complexes are composed of main and auxiliary ligands.Rhodium（Ⅲ）complexes emit near-infrared light at room temperature for the first time,by changing the main ligand,benzene ring was added to the original quinoxaline unit and the phenyl group was changed into thiophene group as the main color,the conjugation was prolonged and the red shift of the complex was realized theoretically.The experimental data show that there is a great difference in the photophysical properties between the two series of complexes by changing the structure of the host ligand.The dpbq series can emit phosphorescence at765nm,the phosphorescent emission peak of dtbq complexes lies at 795 nm.In addition,the complexes in the film state have weak luminescence in the near-infrared region.The absorption phosphorescence life of the complexes is generally short and has no value,and the emission phosphorescence life is relatively high,the complexes with-CF₃group have longer emission lifetime than the other two complexes.